Impact of increased outer wall rotation on convection in a vertical annulus with a stationary heated inner cylinder

Abstract

AbstractThe interplay of centrifugal and buoyant forces on convective heat transfer in a vertical annulus formed by rotating adiabatic outer cylinder and stationary heated inner cylinder has been experimentally and numerically investigated. Experiments were performed for rotational speeds corresponding to the rotation parameter ζ in the range of 527 ≤ ζ ≤ 2860, maintaining the heat flux of the heated stationary inner cylinder as 80 W/m2, for radius ratio (η) and aspect ratio of the vertical annulus being 0.614 and 0.052, respectively. The problem was investigated numerically using the commercial computational fluid dynamics package, ANSYS CFX. The numerical methodology has been validated by comparing the numerically predicted average surface Nusselt number with experimentally obtained values. The comparison revealed an enhancement of the thermal performance of the heated stationary inner cylinder in the range 527 ≤ ζ ≤ 1190 due to the increase in turbulence intensity towards the heated inner cylinder. However, when the rotation parameter was increased further in the range 1190 ≤ ζ ≤ 2860, the thermal performance of the stationary heated inner cylinder showed only marginal improvement. The aforementioned thermal behavior of the inner heated stationary cylinder has been explored based on the flow statistics gathered from the numerical simulations.